1. Field of the Invention
The subject invention relates to an ignition and transmission shift lever interlock system for a vehicle, and more specifically to an interlock system that prohibits removal of an ignition key from an ignition switch while permitting disconnection of an accessory circuit with a transmission shift lever and shaft of the vehicle in a neutral position or a drive position.
2. Description of the Prior Art
Vehicles including an automatic transmission currently include an ignition transmission shift lever interlock system to prevent movement of a transmission shift lever out of a park position unless the key is in an ignition switch and the ignition switch is unlocked, i.e., in an accessory position or in a start/run position.
The interlock system comprises a shaft, which defines a longitudinal axis. The shaft is rotatable about the longitudinal axis between at least a park position, a neutral position, and a drive position. The transmission shift lever is pivotably coupled to the shaft and is pivotably moveable relative to the shaft between a restrained position and a release position. The shaft is rotatably moveable between the park position, the neutral position, and the drive position when the transmission shift lever is in the release position. The shaft is restrained in the park position when the transmission shift lever is in the restrained position. The ignition switch includes at least an off position, an accessory position, a start position, and a run position. The ignition switch is only moveable into the off position when the shaft is in the park position. An inhibitor pin is coupled to the ignition switch by a push/pull cable. The inhibitor pin is stationary relative to rotation of the shaft about the longitudinal axis, and is moveable along the longitudinal axis between a lock position and an unlock position. In the lock position, the inhibitor pin is engaged with the transmission shift lever when the ignition switch is positioned in the off position. In the unlock position, the inhibitor pin is disengaged from the transmission shift lever when the ignition switch is positioned in the accessory position. The vehicle draws an electrical current from an accessory circuit when the ignition switch is in the accessory position. The accessory circuit is disconnected when the inhibitor pin is moved axially along the longitudinal axis into the lock position.
Vehicles also usually include a key removal inhibitor system. The key removal inhibitor system prevents the removal of the key from the ignition switch when the transmission is not in the park position.
Certain manufacturing facilities require the transmission of the vehicles and thereby the transmission shift lever and the shaft, to be positioned in the neutral position for movement along a production line. In order to place the transmission in the neutral position, the ignition key is inserted into the ignition switch and turned to the accessory position, thereby unlocking the ignition switch. Upon unlocking the ignition switch, the inhibitor pin is moved into the unlocked position and the transmission shift lever is released from the restrained position, thereby permitting a user to shift the transmission of the vehicle into the neutral position by rotating the transmission shift lever and the shaft about the longitudinal axis. Once the shaft is rotated about longitudinal axis, the inhibitor pin abuts the shaft, preventing the inhibitor pin from moving along the longitudinal axis into the lock position, thereby preventing disconnection of the accessory circuit. As a result, the ignition switch is locked in the accessory position, and the vehicle continuously draws the electrical current from the accessory circuit. Continued draw of the electrical current results in discharge of the vehicle battery, which is not desirable. It would therefore be desirable to have the capability to disconnect the accessory circuit while the transmission shift lever and the shaft are in the neutral position while maintaining the integrity of the key removal inhibitor system.